Download Annual Report 2012 - Wyoming Cooperative Fish and Wildlife

American Pika Status in Wyoming
Annual Report for Wyoming Governor’s Big Game License Coalition
Anna D. Chalfoun, WY Cooperative Fish & Wildlife Research Unit,
Dan Doak, Department of Zoology & Physiology, University of Wyoming, and
Leah Yandow, MS Candidate, Dept. of Zoology & Physiology, University of Wyoming
We have completed our fieldwork portion of this study as of September 2011. Our main
objectives for the season were twofold: 1.) Establish and survey in a geographically
distinct mountain range, the Bighorns, with sites covering a similar yet broad gradient of
topography and climate as sites in the Wind River Range surveyed in 2010 in order to test
the generality of patterns observed in the Winds and 2.) Revisit all sites from 2010 to pick
up temperature sensors and to resurvey a subset of sites to test for annual differences.
Forty sites in the Bighorns were surveyed for scat and at a subset of these temperature
sensors were deployed to measure potential microclimate variables experienced by pikas
during summer. Survey sites for measuring relative pika abundance indicated by scat/m2
were selected a priori based on the habitat and climate characteristics we are interested in
testing. Results show clear patterns of relative abundance in relation to habitat
measurements.
Preliminary analyses suggest strong support for forage availability and elevation as
important predictors of pika abundance in both mountain ranges. We ran a set of 39
general linear models based on intentionally selected predictor variables to test three
hypotheses (summer heat, winter snowpack and forage availability) for what might be
most limiting for pika populations at this latitude. We then followed up with model
selection procedures, specifically AICc, to determine the likelihood of the best-supported
model given the data and candidate set of models. The top models within two AICc had
varying terms for forage availability metrics and elevation, showing support for these
variables. The elevation data suggest a potential ceiling effect on abundance whereby pikas
exist at lower abundance at our lowest and highest elevation sites in both ranges. These
results suggest that pikas may not simply be able to migrate upslope with on-going climate
change as many have suggested.
L. Yandow presented preliminary project findings at the National Wildlife Society meeting
in Hawaii and the Wyoming Chapter of the Wildlife Society annual meeting December
2011. Further investigation on identifying the specific climate variables indexed by
elevation at our sites is the focus for spring 2012. To address this question, we are using
remotely-sensed climate (temperature and snowpack) and temperature sensor data into
our model selection analyses.
These data and our results will ultimately be shared with WGFD, the US Forest Service,
Tribal Fish and Game, as well as presented at professional meetings and published in a
peer-reviewed scientific journal.
Given predicted on-going climate change, its potential impacts to alpine systems, and the
potential for the American pika to serve as a sentinel species for such change, we believe
that our research will constitute an important contribution. Moreover, to our knowledge,
ours is the first systematic study of the pika in Wyoming, which will render threat
assessments for the species at our latitude more do-able. Thank you for your support.